Internal combustion engines often have components sealably connected to them that perform various functions. Examples of such components include valve covers, oil pans, thermostat housings, and so forth. One common trait of such components is that they are mounted to a base engine structure by fasteners that are secured to the base engine structure and clamp the component through a bolt opening formed in a flange of the component. One other common trait is that, usually, these components sealably contain an internal volume of the engine that contains fluids. Gaskets or other types of seals are generally placed at a flange interface between such a component and the base engine structure. A placement of the fasteners to connect the component to the engine around a periphery of the flange interface is typically determined according to the “clamp load” that is desired on the seal. The clamp load is a pressure applied locally to the seal from an adjacent fastener.
Typical design guidelines require a uniform clamp load around a periphery of a sealed flange interface for proper performance of the seal therebetween. This typically results in a relatively larger number of fasteners used to secure a flange interface for proper sealing than the number of fasteners needed to carry any stresses in the interface. The larger number of fasteners used is not only more costly, it also presents issues when serviceability and access considerations make it difficult to remove some of these fasteners for service.
Accordingly, there is a need for an improved sealed flange interface configuration that is capable yielding an adequate clamp load for a seal with use of a minimal number of fasteners.